Another option is to treat the piece as a cadenza. Just know that you will need to manually insert \bar "" in places to permit line breaks.
Or use barAlways and defaultBarType:
\version "2.22"
\layout {
\cadenzaOn
\set Timing.barAlways = ##t
\set Timing.defaultBarType = ""
}
\relative {
\repeat unfold 20 { c'4 d e f g }
\repeat volta 2 { c d e }
\repeat unfold 20 { c4 d e f g }
\bar "|."
}
Lukas
